Electrically indicating weft detector for loom



April 18, 1961 A. J. HERARD, JR., ETAL 2,980,147

ELECTRICALLY INDICATING WEFT DETECTOR FOR LOOM Filed July 19, 1957 lNVENTORS ARCHIBALD J. HERARD, JR.

VICTOR F. SEPAVIGH ATTORNEY ELECTRICALLY INDICATING WEFT DETECTOR FOR LOOM Filed July 19, 1957, Ser. No. 673,006

8 Claims. (Cl. 139-273) This invention relates to improvements in an electrically indicating weft detector for loom, more particularly of the side slip type, and it is the general object of the invention to provide an adjustable actuator between the side slipping finger and an arm on an electric switch which when moved changes the condition of the switch.

A side slipping detector generally employs a finger movable about a pivot and having its detecting surface ofiset relatively to the pivot with respect to the direction of back and forth motion of the lay. When sufficient weft or continued weave is present on the bobbin the detector finger does not slip but moves bodily forwardly. If, on the other hand, the weft is substantially exhausted the finger will slip along the bare surface of the bobbin without being moved forwardly bodily and this slipping condition is utilized to bring about a change in the loom operation, such for instance as weftreplenishment.

When detector fingers of the kind already described have been used in the past to close an electric circuit the finger itself has engaged the contact and there has been little or no chance to efiect an adjustment between the swing of the feeler and the contact.

normal angular motion when indicating weft exhaustion and there has been no way in which the contact could be closed without in some way interfering with the setting for the angular motion of the feeler finger.

It is an important object of the present invention to provide an actuator operatively interposed between the side slipping detecting finger and a moving part of the electric switch and provide for adjusting this actuator angularly in a manner which will not interfere with the normal angular swing of the finger.

It is another object of the invention to provide a weft detector with a snap action limit type electric switch provided with an external arm which when moved changes the condition of the switch, and provide for movement of this arm by an actuator which is adjustable angularly with respect to the detector finger, thereby permitting the arm to be held in a normal position very close to the critical position in which it changes the condition of the switch. With such an arrangement only a slight amount of motion on the part of the detector finger is required to move the arm from its normal to its critical position. The normal position of the arm is determined by adjusting the actuator to change the position of a curved surface thereon relative to the switch arm.

In the type of weft detector illustrated herein the finger is mounted on a carrier which slides back and forth on a fixed support and when the finger engages a sufficient supply of weft the carrier is subjected to an abrupt forward motion which has been found to cause undesired closing of the switch unless the latter is mounted in such manner that the forward movement of the carrier can have little or no tendency to close the switch. It is a further object of the invention to mount the switch on the carrier in a manner that the movable parts of the switch will not be affected by motion of the carrier.

Furthermore, the detector finger will ordinarily be set to have a limited When the switch is thus mounted the external arm which engages the aforesaid actuator can be set close to its critical position without risk that motion of the carrier will cause an undesired change in the switch.

Some side slipping weft detectors have a tendency to vibrate slightly. during loom operation with occasional likelihood that a false indication will be given. By reason of the actuator set herein allowance can be made for this vibration without risk of undesired indication by the detector.

In order that the invention may be clearly understood reference is made to the accompanying drawings which ilustrate by way of example the embodiments of the invention and in which:

Fig. l is a plan view showing a weft detector with the invention applied thereto,

Fig. 2 is an enlarged vertical section on line 2--2, Fig. 1,

Fig. 3 is a perspective view of the actuator, and

Fig. 4 is a view of the interior parts of an electric switch which is utilized with the invention.

Referring more particularly to Figs. 1 and 2, a back and forth sliding carrier 10 is mounted on a fixed support 11, part of which forms a stop 12 for a screw 13 adjustable backwardly and forwardly in the carrier 10 and another part 14 of which extends to some fixed part of the loom. -A coil compression spring 15 has the forward end thereof in engagement with a lug 16 which is part of the fixed support 11 and has the rear end thereof in engagement with a second lug 17 formed on the carrier. The spring holds the carrier in its normal rearward position shown in Fig. 1 but yields to permit forward motion of the carrier when such yielding is required.

The carrier is formed .with an oifset arm 20 to which is secured an upright pivot stud 21 the upper part of which is surrounded by a spring holder 22 held in angula'rly adjusted position with respect to the stud by set screw 23. A spring 24 has the upper end 25 thereof engaged with part of the holder 22 and has.the lower end thereof 26 engaged with a normally stationary detector side slipping finger 27. The latter has a forwardly extending lug 28 which is normally held against a stop screw 29 on the carrier by the spring 24.

The finger 27 extends rearwardly from the pivot 21 in a diagonal direction and is provided in the present instance with a weft engaging spring 30 the coils of which penetrate yarn, when present, on a bobbin 31. When the parts are in the full line position shown in Fig. l and there is a sufiicient supply of weft on the bobbin 31 the finger will be moved bodily forwardly without angular motion and will cause a corresponding forward motion of the carrier. If, on the other hand, the finger engages a bare part of the bobbin 31 or an insufiicient supply of weft it will then be swung around pivot 21 to the dotted line position shown in Fig. 1 as the bobbin is moved forwardly to the dotted line 32.

The matter thus far described is usual in mechanical weft detectors, the forward motion of the carrier 10 ordinarily being utilized to disable means which would otherwise cause a change in loom operation but remaining stationary and therefore initiating a change when the finger moves angularly to the dotted line position.

In carrying the present invention into efiect the carrier it? has secured thereto a stand 35 which may be made of sheet metal and having a top part 36 held to the aces, is?

a is fixed with respect to the carrier to move backwardly and forwardly therewith.

I The switch has an external sheet spring arm 45 mounted on an insulated base 46 of the switch and having rotatable on the rear end thereof a roll 48. The arm engages a plunger or force transmitter 50 which is slidable on the base 46 in a direction substantially at right angles to the direction of back and forth motion of the carrier which has its axis in alignment with the axis of pivot 21. Further details of the detector will be set forth hereinafter.

An important part of the present invention concerns an actuator generally indicated at 55 shown in detail in Fig. 3 and having an upper part 56 provided with a hole 57 which receives and freely encircles the stud 21 as shown in Fig. 2. The stud serves as a pivot for the actuator when the latter is adjusted with respect to the finger 27. The lower part 60 of the actuator is located on said finger remote from stud 21 and is provided with a slot 61 preferably arcuate with respect to the axis of stud 21 and an adjusting screw 52 passes through the slot and is screw threaded into'the finger 27. As can be seen in Fig. 3, upper and lower parts 56 and 60 respectively are joined by a vertical part to maintain said upper and lower parts vertically spaced from each other. By loosening the screw 62 the actuator can be adjusted with respect to the finger 27 around the pivot 21. The actuator which may be in the form of a cam and finger 27 are normally fixed with respect to each other.

The actuator has a curved surface 65 on the upper part 56 thereof for constant engagement with the roll 48. This curved surface which may be arcuate and eccentric with respect to the pivot 21 is of such shape that angular movement of the finger 27 will cause the surface to effect positive movement of the roll 48 and therefore the arm 45. As shown herein the surface 65 is of such form that as the finger 27 moves from the full line to the dotted line position thereof shown in Fig. 1 the roll will be moved away from the stud 21 and move the plunger 50 inwardly relative to the switch.

The external arm 45 when moving to the right from the position shown in Figs. 1 and 4 will reach a critical position and cause a snap action in the switch S which changes its condition. By properly adjusting the actuator with respect to the finger the arm 45 can be moved until its normal position is very close to this critical position so that only a slight angular movement of the actuator induced by the finger 27 will be sufiicient to change the switch. It will be noted that the actuator can be adjusted to vary the position of the arm 45 without requiring a corresponding change in the angular throw of the detector finger 27.

The switch shown in Fig. 4 is of standard manufacture but the manner of its mounting has a bearing on the invention. Referring particularly to Fig. 4, the plunger 50 has the right-hand end thereof formed with a head 70 which engages the rear end of a contactor 71 the forward end of which is movable between two contacts 72 and 73. A small leaf spring 74 has the forward end thereof secured to the forward part of the contact 71 and has the rear part thereof in engagement with a fixed conductor '75 at 75. A metallic arm 77 has the rear part thereof in engagement with the contactor 71 and has the forward part thereof movable pivotally with respect to the contactor 71 at 78. When the switch is in normal position with the parts as shown in Fig. 4- the spring 74 acting on the contact 71 will hold the plunger with its head '74P against a wall of the insulating base 46. As the arm 55 moves to the right, Fig. 4, it will cause the plunger 50 to move the rear end of the contactor 71 to the right to a critical position at which time the spring 74 then snaps the forward end of the contact 71 to the right from the position shown in Fig. 4 to engagement with the contact 72. This will close a circuit from wire 80 through the contact 75, metal part 77, contactor 71 and contact 72 to wire 81 to energize an electric control for the loom (not shown). A cover 82 of insulating material for the switch, shown in Fig. 1, has been onntted in Fig. 4. v p 7 It will be noted that the contactor 71 extends in a back and forth direction and is'not acted on to move relatively to the other parts within the switch when the carrier 10 is moved forwardly. This is one of the reasons why the arm 45 can be moved to a position very close to its critical position by the actuator 55. The arm 45 is also substantially parallel to the direction of motion of the carrier, and the forward part of the contactor 71 moves laterally at right angles to said motion when changing the condition of the switch. Moreover, the force exerted by spring 74 passes through a plane which extends from the axis of pivot 21 to the axis of roll 48 and thence through the axis of plunger 50 in a manner such that the force cannot exert any torque on finger 27 to cause rotation thereof which would result in a false indication of weft exhaustion.

From the foregoing it will be seen that the invention sets forth a side slipping weft detector provided with an actuator adjustable with respect to the side slipping finger and positioned for engagement with the roll 48 to elfect movement of the latter and its arm 45 to change condition of the switch S when the finger 27 moves from the full line to the dotted line position shown in Fig. 1. The detector finger will ordinarily have a fixed range of angular motion but the actuator because of the slot 61 and the screw 62. can be changed angularly with respect to the finger to cause angular motion of the surface 65 around the pivot 21 to vary the normal setting of the arm 45 to effect a rapid or slow change in the condition of the switch when the detector finger moves depending upon which direction the actuator is angularly adjusted. It will also be seen that the switch is so disposed that those parts of it which must be moved to effect a change in its condition extend in a back and forth direction and are therefore not affected by the back and forth motion of the carrier it Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

1. In a loom weft detecting mechanism having a carrier, a pivot on the carrier, a side slipping detector finger mounted on said pivot for a normal angular movement thereabout, an electric switch on the carrier having an arm to be moved to effect a change in the condition of the switch, and an angularly adjustable actuator interposed between said finger and said arm and constantly engaged therewith and having an upper part freely encircling said pivot and a lower part remote from said pivot and fixed to said finger, said upper part having an eccentric surface with respect to the axis of said pivot and capable of being adjusted angularlywith respect to said arm without requiring a corresponding change in the normal angular throw of the detector finger, and said actuator being movable pivotally about said pivot when said finger moves to cause said surface to positively move said arm with respect to said pivot to eifect said change in the condition of said switch.

2. In a loom weft detecting mechanism having a carrier, a pivot on the carrier, a side slipping detector finger mounted on said pivot and set for a normal angular movement thereabout, an electric switch on the carrier having an arm to be moved to eifect a change in the condition of the switch an angularly adjustable actuator between said finger and said arm and movable pivotally about said pivot with said finger and having an arcuate and eccentric surface constantly contacting said arm effective due to angular movement of said actuator around said pivot to move the arm positively with respect to said pivot to effect said change in the condition of said switch and means to adjust the angular position of the actuator relatively to said finger to change the area of contact of said surface which contacts said arm when the actuator swings with the finger, the adjustment of the actuator capable of being made without disturbing the setting for said normal angular movement of said finger.

3. The detecting mechanism set forth in claim 2 wherein the means to adjust includes a slot in the actuator and a screw passing through the slot threaded into said finger and wherein said adjustment when made moves said arm without moving said finger to place the arm in a position to effect a rapid or slow change in the condition of the switch when the finger moves depending upon which direction the actuator is angularly adjusted.

4. The detecting mechanism set forth in claim 2 wherein the actuator when being adjusted relative to the finger swings angularly around said pivot without moving said finger to change the position of said surface with respect to said pivot and said arm.

5. In a loom weft detecting mechanism having a carrier, a pivot on the carrier, a side slipping detector finger mounted on said pivot for a normal angular movement thereabout, an electric switch on the carrier having an arm to be positively moved from a normal position to a critical position which is close to said normal position to effect a change in the condition of the switch, and an angularly adjustable actuator fixed on said finger and movable pivotally about said pivot with said finger and having an arcuate and eccentric surface constantly contacting said arm effective due to angular movement of said actuator around said pivot to move the arm with respect to said pivot, said surface being capable of having its position changed relative to said arm and without moving said finger due to the adjustment of said actuator to vary the position of said arm with respect to said pivot in order to positively maintain said arm close to said critical position in which it changes said condition of said switch, thus necessitating only a slight amount of motion of said finger to move said arm from said normal position to said critical position to efiect said change in said condition of said switch.

6. In a loom weft detecting mechanism having a backwardly and forwardly slidable carrier, a pivot on the carrier, a side slipping detector finger normally stationary with respect to and mounted on said pivot for angular movement thereabout, an electric switch on the carrier having a spring to exert a force in the opposite direction to which an arm on said switch is to be moved to efiect.

a change in the condition of the switch, an adjustable cam element fixed on said finger movable pivotally aboutsaid pivot and having a surface constantly contacting said arm effective due to angular movement of said cam element around said pivot to move the arm with respect to 'said pivot, and means to adjust the angular position of the cam element relative to said finger without moving the latter from its normal stationary position to change the part of said surface which contacts said arm when the cam element swings around said pivot, said switch being of the snap action limittype having a contactor engaging a force transmitting plunger in alignment with the axis of said pivot and extending substantially parallel to the direction of movement ofsaid carrier and moving when acted upon by said plunger at right angles to said last-named direction when changing the condition of the switch.

7. The detector mechanism set forth in claim 6 wherein the part of said arm that engages said surface is in a vertical plane passing through the axis of said pivot and said plunger so as to render said spring incapable of exerting a force to said finger to transmit any torque to the finger to cause a false movement thereof.

8. The detecting mechanism set forth in claim 6 wherein the cam element has a horizontal upper fiat part with a hole to freely receive said pivot and also has a horizontal lower flat part provided with a slot for adjusting purposes and joined to said upper part by a substantially vertical part whereby the latter acts to maintain said upper and lower parts vertically spaced from each other, said upper part having a curvi-lineal cam surface for engagement with said arm.

References Cited in the file of this patent UNITED STATES PATENTS Darwin Mar. 31, 1953 Smith Feb. 20, 1934 

